This invention relates generally to a safety stop push button feature that could be used on most any push button activation mechanism to prevent unwanted activation of the push button. This invention has particular applicability for use in a spring actuated safety introducer needle assembly which may be used with an intravenous (IV) catheter.
With the advent of acquired immune deficiency syndrome (AIDS) and other infectious diseases, there has been much concern with accidental needle sticks of healthcare workers by used IV catheter introducer needles. As a result many companies have attempted to develop a safety needle system that would allow the healthcare worker to shield the sharp distal tip of the needle after the catheter has been placed in a patient's vein. One such system is shown in U.S. Pat. No. 4,747,831, the disclosure of which is hereby incorporated by reference.
In that system, the needle hub and introducer needle are slidably disposed in a hollow barrel with the sharp distal tip of the needle initially extending beyond the distal end of the barrel. A spring is located between the needle hub and the distal end of the barrel. A latch is used to keep the needle hub adjacent to the distal end of the barrel so the sharp distal tip of the needle extends beyond the distal end of the barrel. After the introducer needle and catheter have been properly inserted into the patient's vein, the latch is activated allowing the spring to force the needle hub to the proximal end of the barrel. As a result, the sharp distal tip of the needle is withdrawn into the barrel out of reach of the healthcare worker.
Although the above described device works for its intended purpose, it could be improved. Since the device is spring activated, movement of the latch will allow the spring to withdraw the needle into the barrel. Unfortunately, in certain circumstances, the healthcare worker may inadvertently depress the latch prior to the catheter being properly placed in the patient's vein.